#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>

int main()
{
	int n = 0;
	int i = 1, product = 1;
	
	scanf("%d", &n);

	for (i = 1; i <= n; i++)
	{
		product = product * i;
	}

	printf("%d", product);
	return 0;
}